Julie Strange took the dramatic action after the DVLA repeatedly sent letters to her dead son Paul alleging he had failed to inform them about the sale of a mystery vehicle.
She was even contacted by bailiffs wanting to seize the vehicle.
Some time later a summons was delivered to her home at Little Salkeld, near Penrith, Cumbria, asking Paul to appear before magistrates in Workington.
The 43-year-old had repeatedly contacted the DVLA to explain that her son, aged 19, had died in 2006 and had never owned the vehicle in question.
She even sent them a copy of his death certificate.
However, the authority carried on sending letters.
Mrs Strange brought her son's ashes into the courtroom at Workington Magistrates in a wooden casket with his name engraved on a plaque on top of it.
The prosecution withdrew the case and presiding magistrate Jack Abernethy asked her to accept the condolences of the bench and court staff.
Mrs Strange, who is married with two other children, said after the hearing: "I thought long and hard about doing what I did today.
"But I was really worried that if I didn't turn up then Paul would be found guilty in his absence and fined. Then he would be pursued by the courts as well.
She added that she hoped the DVLA would send the family an apology: "I just hope this is the end of it.
"This has been really traumatic for the whole family."
Paul, who worked at Gregg's bakery in Penrith, died on October 16, 2006, after being hit by a train just north of the town's railway station.
It was almost a year before the first letter came from the DVLA saying he had not lodged details with them about a vehicle which he had allegedly owned.
A spokesman for the DVLA said they did not comment on individual cases.